Variable tuning device



Nov. 10, 1931.

E. G. DANIELSON VARIABLE TUNING DEVICE Filed July 13. 1927 2 Sheets-Sheet 1 Illlllllll HIIIIII lilmulllm IIIII A TTORNE YS Nov. 10, 1931. l E. G. DANIELSQN 1,830,982

` VARIABLE TUNING DEVICE Fiied July 13. 1927 v 2 sneetslsheer 2 INVENTOR: Wig/2e?? Gffam'elsa/r Mig/ww ATTORNEYS.

Patented Nov. 10, 1931 UNITED-,"STATES PATENrorFicl-;

ERNEST G. IJANIRLsoN,v or SAN-FRANCISCO, ,cAIiIroRNIL VAssi'crixioii.,roeRAIr &

nANIRLsoN MANUFACTURING COMPANY, orsAN rRANcisco, oALIroRNIA, A co- PAR'INERSIIIP coNsIs'rINe or ERNEsr (c+. nANIriIisoia' AND THoMAs R. yGRAY v vARIARLR TUNING imi/Ion i Y 'Appiicaiionvmediuiy 1a, i927..l serial No. aoaefil-' This invention relates generally to devices for effecting tuning of electrical circuits, and isfparticularly adapted for use with radio receiving systems.

It is an object of this invention to devise a manual control for a variableV tuning instrument, which will be simple inl construction, will eliminate all back lash and will be smooth iny operation.-

It is a further object of this invention to -devise a convenient mounting for a variable tuning instrument which will incorporate a novel form of manual control.

It is a further object of this invention to ydevise a novel form of indicating drum forv a variable tuning' device.

Further objects of this invention will appear from the following description in whichV I have set forth/the preferred embodiment of my invention. It is to be understood that the appended vclaims are to be accorded a range of equivalents consistent with the state of the prior art. Y

Referring to the drawings:

Figure 1 is a top plan view illustrating a -Y tuning instrument provided with a control constructed in accordance with this invention. Fig. 2 is a side elevational view of the tuning instrument shown in F ig. 1.

Fig is a front view ofthe timing instrument and its control, with the instrument being mounted behind an instrument panel. 1

hg. 4 is a cross sectional view taken along the line 1 -4 of Fig. 1. f Y A In the mountingof variable-condensers or other tuning devices behind the front panel of a receiving cabinet, it has previously been proposed to arrange the condenserin such a way that its shafty is parallel to the plane of the instrument panel and then to manually rotate the condenser shaft` by means of'ra rotatable control shaft extended thru the panel. This arrangement is usually utilized with a drumtype of indicator having a minor portion of its periphery visible thru. aV window in the instrument panel. It is advisable :to have v the control shaft located comparatively close to the panelr Window, but in order, to prevent ,50 the operators hand from obstructing the view tunin g instrument. e

of the indicating drum, it isadvisable olf'- set the control shaft either above or below the window. A variety of mechanisms have been employed for operatively connecting the vinstrument sliafttoV the rotatable control shaft, asfor example belts and pulleys, chains and sprockets, and Y worm gear drives. The belt and pulley mechanism. is* yobjectionable since the iiexible cord or. belts employed must be replaced at frequent intervalsand slippage may occur if the belt lstretches sufficiently. The chain drive gives a Jerky, uneven movement to the instrument.shaft,.while both the chain andworindrives provide an excessive amount of baci; lash. In this invention these U `difculties have been eliminated by the use of a simple helical gearandpinion. y.Afdrive v,connection of this lrind is notonly cheaper to manufacture,but it also possesses-inherent characteristicsy whichl make it particularly adaptable for use as a control for a variable Referring tothe drawings for afcomplete description of the invention, there is showny a variable tuninginstrument 10, as for ex-l ample a variable `condenser of the type Vsuch f as disclosed in my Patent No. 1,589,946 issued J une 22, 1926'and entitled Variablecondenser. A cond-enserof this type includes a pair of electrodes 11 which are pivotally mountedl on a suitable insulating base 12.VVV These electrodes are caused to move relative to each other by use of a pair ofv interineshing gears 13, which vin turn are rotated bymeans of a pinion 14 secured to a rotatable instrument shaft 16.

In order to conveniently support the variable tuning instrument 10 behind an instru*- ment panel 18 of a radio receiving set, there is provided'a metal plate 19 toffwhicli the nvsulating-base 12 is secured asby means of screws 21. The plate 19'is preferably reinforced -as by means of integralflanges 22 formed along the edges'vof thev same, and is also provided with an integral'flange 23 vwhereby the plate may be secured to the rear side of the, instrument panel 18 in such apositionthat itextends substantially perpendicular thereto. Ihe instrument `shaft 16 progectsthru' the'zplate 19'norm`ally thereto, and(A accordingly is. arranged substantially4 fio ably secured to the instrument shaft 16 as by means of set screw 28. The gear 24 and shaft 16 are adapted to be manually rotated by means of a rotatable control shaft 31 which preferably extends adjacent one side of plate Y19 and parallel thereto. One end of shaft 31 is jouriialed within aferrule 32, this ferrule being threaded into the struck in portion 33 of flange 23, and the other end of the shaft is retained between a pair of integral struck out projections 34. The bearing for this portion of the shaft is formed by a journal block 36 which is slidably retained between the projections 34. ,Positioned upon the control shaft 31 so as to mesh with the gear 24, there is a gear of pinion 37 which is likewise provided with helical teeth. Gears ofthis type arecalled twisted gears. A leaf spring 38 is provided which presses against Vthe journal block 36 and serves to resiliently urge the pinion and gear together, thus eliminating Vall back lash. That end of the shaft 31 which projectsthru' the instrument panel 18, may beprovided with convenient control knob 39. ln order to aid in keeping the pinion in pei'- fect mesh-With the gear 24, the shaft 31 is preferably interrupted and a suitable flexible `coupling 41 is inserted to interconnect the adjacent shaft ends. This coupling for example may be in the for-m of a tightly womid helical spring as shown, the ends of the spring being secured to the adjacent shaft ends.

TWith the arrangement such as described above it will be noted that the control shaft 31 is odset a substantial distance from the axis of the instrument shaft 16. In some 1nstances it is desirable to place the control shaft 31 above the instrument shaft 16 or to Y invert the plate 19 and still have the control shaft 31 below the instrument shaft. To permit this result, the plate 19 is providedwith l duplicate means for journaling the shaft 31 upon either side of the instrument shaft. rlhus the plate has been shown as provided with an internally threaded portion 133 corresponding to the threaded portion 33 prerviously described, and also with integral struck out projections 134 similar to the projections 34 previously described.

In order to provide convenient means whereby the operator mayjudge the relaxes tive position of the instrument shaft 16, there is provided an instrument drum 43 which is rotatable with shaft 16' and-Which hasits eriphery visible thru-a window- 44 in theV instrument panel 18. A convenient way to construct this indicating drum is to provide a pair of meta-l discs 46 retained apart in spaced relationship as by means of spacing members 47. Spacing members 4 7 likewise serve to permanently Secure the drum to one face of the gear 24. The peripheral edge of each disc 46 is bent to provide an inwardly faced groove 48, these grooves serving as a meansiior slidably engaging the edges `of a flexible indicating strip 49. This indicating strip is shown in F ig. 1 and preferably contains'graduations 51 of any desired character. lt is preferably provided with an inscribable si'irface'whereby any desired legends may he Written directly upon it thru the Window 44. Where. the ends of the indcatihg strip. 49 overlap es showiiin Fig. 1, the discs 46 are preferably provided with alhedv slots 52 whereby 'one end of the strip may be engaged and pulled outwardly so that the entire strip may be slid within. the grooves 4,8 AMld-thereby removed from the drum. A new indicating strip may thenbe inserted thru the slots 5.2 and slid about the dr-uin until it occupies the desired position.

The Window 44 thru which the indicating drum is viewed, isk preferably formed in an inset portion` 5.4 Of lmetal plate 56. In order to illuminate that portion of; the drum which is viewed, theremay be. provided a Small electric lamp globe 5.7' inserted in a suit-,able socket 58. which is mounted upon one of theianges 22. of plete i9.` A slight space is left between the inner edges of the inset portion 54 and, the periphery of the indicatieg drum, and light .57 isL positioned directly above or below the inset portion 54 so as to project its light down between this'portion 5.4 and the, drum periphery, thus aording au indirect lighting effect.

lt, will he. obvious .from the above description that have. provided a simple and effectivev control for the variable tuning instrument which may either he sold separate l ly for` use with anystandard tuning instrument orwhich may be Sold together with a timing instrument as a complete unit. I desired the control device may also be incorporated with a plurality of tuning instrunichts so es te form what is commonly known as a gang control. To facilitate. coupling of one or more additional instruments to the shaft the indicating drum 43 is provided with an aperture 6,1 Vwhereby the shaft of another instrument may be Coupled to an arial stud 62 provided ron the hub of gear 24- They inclined or helical shape of the. gear teeth afford a sliding action, which. makes the control perfectly smooth,V and even.` teeth need not be machine cut but maybe pressed into the edge of flange 26 by al knurling tool. I claim: Y g

1. In a-device of the class described, a

The"

plate adapted to be securedl to an instrument panel, a variable tuning instrument mounted onV one side of the plate, said instrument having a rotatable shaft projecting thru the plate, a control shaft disposed substantially parallel to said plate and offset to one side of said instrument shaft, means formed on said plate for journaling said controlshaft, drive means for operatively connecting said shafts, and additional means formed upon said plate for journaling said control shaft upon the opposite side of said instrument shaft.

2. A mounting and control for a variable tuning device comprising a plate to which said device can be mounted, said device having a rotatable shaft adapted to project thru said plate, a rotatable control shaft, a pair of spaced membersl mounted on said plate and forming a slot within Which said control shaft is j ournaled, said control shaft 'extending substantially at right angles to the shaft of said device, a gear fixed to the shaft ofV said device, a. pinion on said control shaft, and resilient means normally urging the control shaft in a direction to force said gear and pinion into engagement.

3. In a device of the class described, a plate adaptedto be disposed at substantially right angles t0 an instrument panel, a variable tuning'instrument mounted on one side of said plate, lsaid instrument having a rotatable shaft projecting thru the plate, a control shaft disposed substantially parallel to said plate and offset to one side of said instrument shaft, means formed Lon said plate for journaling said control shaft, drive means operatively connecting said shafts, and additional means mounted on said plate for journaling said control shaft upon the opposite side of said instrument shaft. V

4. In a radio receiver the combination with a front panel having control means thereon, of tuning means to the rear of said panel, a drum member carrying indicating means on its circumferential periphery, said drum member being coupled with tuning means, a circular flange formed along the base of said drum member, and offset from the outer periphery of said drum member, a shaft extending from said control means through said panel, and driving means on the shaft, coacting with said dangewhereby to actuate said drum and said tuning means. Y

5. In a radio receiver the combination with a front panel, having control means thereon, of tuning means to the rear of said panel, a drum member carrying indicating means on its circumferential peripher ,j said drum member being coupled with said tuning means, a. circular flange formed along the base of said 4drum member and offset fromV the outer periphery Vof said drum member, a shaft extending from said control'means through said panel, and driving means on the shaft, coacting with said flange, whereby to actuate said drum and said tuning means and means for maintaining the pressure ofsaid driving means, whereby to provide for constant contact of the same against the ange on said drum.

6. In a radio receiver, the combination with a panel, of control means to the front of said panel, a shaft fixed to the control'` means and passing to the rear of said panel, tuning means to the rear of said panel, a drum member carrying indicating means on its circumferential periphery, said drum being coupled with tuning'means and positioned to the rear of said panel, an" aperture in said panel through which a portion of said indieating means may be visible, and anannular projection formed on the base of said drum adjacent the circumferential periphery there-- of, and means on said shaft for contacting l with said projection, whereby to actuate the drum member and the tuning means.

In testimony whereof, I have hereunto set my hand. Y

ERNEST G. DANIELSON. Y

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